Simultaneous Detection of Lactate Enantiomers Based on Diffusion-controlled Bioelectrocatalysis

Area of Science:

• Electrochemistry
• Biosensors
• Enzyme kinetics

Background:

• Lactate enantiomers (L- and D-lactate) play crucial roles in biological processes.
• Simultaneous and accurate detection of lactate enantiomers is essential for clinical diagnostics and metabolic studies.
• Existing detection methods may lack specificity or require complex sample preparation.

Purpose of the Study:

• To develop and characterize an amperometric biosensor for the simultaneous detection of L- and D-lactate enantiomers.
• To investigate the enantioselectivity and performance of the biosensor system.
• To demonstrate the practical application of the biosensor in analyzing biological samples.

Main Methods:

• Construction of amperometric biosensors using NAD-dependent L- and D-lactate dehydrogenases.
• Immobilization of Meldola's blue on mesoporous electrodes for NADH oxidation.
• Amperometric measurements in a two-electrode system with Ag|AgCl|sat. KCl counter electrode.
• Characterization of sensor response time and sensitivity for both enantiomers.

Main Results:

• The biosensor achieved simultaneous detection of L- and D-lactates with high enantioselectivity.
• Stable amperometric measurements reached a pseudo-steady state within 60 seconds.
• Sensor response was influenced by lactate diffusion at the electrode edge, ensuring reproducible measurements.
• The biosensor was successfully applied to detect L- and D-lactates in horse serum samples.

Conclusions:

• The developed amperometric biosensor offers a reliable method for simultaneous lactate enantiomer determination.
• The sensor's design, utilizing enzymatic reactions and modified electrodes, provides excellent sensitivity and reproducibility.
• This technology holds potential for applications in clinical diagnostics and biochemical analysis.